GMP Tools part 34584 is a replacement bearing for cable blowing machines, specified as bearing reference 600 with 2RS sealing. The 2RS designation means rubber seals on both sides, which keeps duct dust, grit and lubricant out of the raceway and the grease in, extending service life in dirty outdoor conditions. Blower drive and roller bearings are consumable items, and replacing them on schedule prevents drag that costs blow distance. Ordered by fiber contractors maintaining their own blowing equipment. Millennium part #526427.